When a crash or collision occurs, a driver can be thrown forward against the steering wheel with great impact.
It is desirable to provide a controlled collapse of the steering column to reduce the force of impact against the driver. The steering column will collapse, but it also tends to rise to a greater angle upon frontal impact, caused by the forward component of the force of the driver against the steering wheel. The rise of the steering column places the steering wheel/air bag assembly in an unfavorable position with respect to the driver. Accordingly, it is desirable not only to provide for a controlled collapse of the steering column, but also to prevent this tendency of the steering column to rise to a greater angle.
In accordance with the present invention, the steering column, which normally extends downwardly and forwardly from the steering wheel, is supported by a mounting bracket. The mounting bracket is secured to the steering column and to vehicle support structure. The connection to the vehicle support structure is releasable upon a frontal impact of sufficient severity, allowing the steering column to collapse in the direction of its length, that is, forwardly and downwardly.
More specifically, the mounting bracket is secured to the vehicle support structure by fasteners which extend through and are connected to longitudinal slots in the bracket. The connection of the fasteners in the slots is releasable in response to longitudinal collapse of the steering column in a frontal impact. There may be four such fasteners and two or more may be in the form of capsules.
Further in accordance with the invention, a pull loop assembly is associated with at least two of the fasteners. Each pull loop assembly includes an elongated, generally U-shaped strap of flexible, bendable, material having a first leg connected at one end to one of the fasteners and a second leg having an unattached or free end. Each strap has a return bent intermediate portion extending over a fixed part of the mounting bracket so that when the bracket collapses with the steering column the straps will unwind around and be pulled over the fixed part of the mounting bracket, absorbing energy in the process. Preferably the fixed part of the mounting bracket over which each strap extends is a separate support frame made of plastic or similar material fixedly attached to the mounting bracket.
The mounting bracket underlies certain vehicle support structure which prevents the bracket, and hence the steering column connected thereto, from rising. Accordingly, the steering column is guided in its collapsed configuration, but is also prevented from rising.
One object of this invention is to provide support structure for a steering column of a motor vehicle having the foregoing features and capabilities.
Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.